Changes In Free Amino Acids Research Articles

Changes of Free Amino Acids in Skeletal Muscle and Serum after Exercise Injury

Changes of Free Amino Acids in Skeletal Muscle and Serum after Exercise Injury

Chemical and sensory changes during shelf-life of UHT hydrolyzed-lactose milk produced by “in batch” system employing different commercial lactase preparations

Manufacturing shelf-stable Ultra-high temperature hydrolyzed-lactose milk (UHLM) is a challenge for dairy producers, as the product undergoes chemical changes during storage due to both reducing sugars reactivity and proteolysis arising from the impurity of the lactase preparations. In the present study, the “in batch” production system, which includes the addition of the lactase before the thermal treatment, was demonstrated a valuable alternative to the more popular “in pack” system, where lactase is added directly into each milk package after thermal sterilization. The features of the technology were investigated by monitoring the changes in free amino acids, volatile organic compounds, color and sensory properties of UHLMs produced with three different lactase preparations (LPs), up to 120 days at 20 °C. Upon UHT processing, the proteolytic side activity of lactases was minimized, so minimum breakdown of milk protein was achieved. The release of free amino acids was dependent on the lactase purity only in the early production phases, whereas it did not change over time. The Strecker aldehydes benzaldehyde and 2-methylbutanal resulted as effective markers to correlate with the initial lactase purity during storage. Color and sensory slightly changed during storage but were poorly correlated with the different lactases, resembling to phenomena typical of milk aging. This latter result suggested that production costs might be lowered by opting for less-purified lactases when considering the “in batch” technology, supporting the application of this production system for the design of UHLM with high-quality standards and low risk of alterations during shelf-life.

Seasonal Changes in Free Amino Acid and Fatty Acid Compositions of Sardines, Sardina pilchardus (Walbaum, 1792): Implications for Nutrition.

The aim of this study was to clarify the seasonal variation in the proximate composition of the free amino acid (AA) and fatty acid (FA) profiles of the European sardine (Sardina pilchardus) from the Adriatic Sea and to better understand the nutritive value needed to organize more effective industrial processing, aquaculture use and to ensure the health benefits for consumers through available bioactive compounds such as omega-3 FA and essential AA. The lipid content ranged from 1.18 to 10.58% during the year, being the highest from July to September. For the first time, this paper reports the monthly variation in AA content in sardines. The highest total AA content was measured during the winter period, from January (843 mg/100 g fillet) to March (953 mg/100 g) with histidine, arginine and threonine being the most dominant. The total content of essential free AA (histidine, threonine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan and lysine) ranged from 137 to 571 mg/100 g fillet (wet weight), recorded in May and March, respectively. The fatty acid profile analyses revealed the major saturated FA as palmitic (C16:0), followed by myristic (C14:0), and stearic (C18:0) acids, and the predominant monosaturated FA as oleic (C18:1n–9) and palmitoleic (C16:1n–7). The high concentrations of polyunsaturated FA in sardines were omega-3 FA, particularly eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic (DHA; 20:6n-3) FA. From July to September, their content was the highest (>3.5 g/100 g of sardine fillets), confirming that these species are excellent sources of bioactive lipids.

Strategies in a metallophyte species to cope with manganese excess.

The effect of exposure to high Mn concentration was studied in a metallophyte species, Erica andevalensis, using hydroponic cultures with a range of Mn concentrations (0.06, 100, 300, 500, and 700mgL-1). At harvest, biomass production, element uptake, and biochemical indicators of metal stress (leaf pigments, organic acids, amino acids, phenols, and activities of catalase, peroxidase, superoxide dismutase) were determined in leaves and roots. Increasing Mn concentrations led to a decrease in biomass accumulation, and tip leaves chlorosis was the only toxicity symptom detected. In a similar way, photosynthetic pigments (chlorophylls a and b, and carotenoids) were affected by high Mn levels. Among organic acids, malate and oxalate contents in roots showed a significant increase at the highest Mn concentration, while in leaves, Mn led to an increasing trend in citrate and malate contents. An increase of Mn also induced an increase in superoxide dismutase activity in roots and catalase activity in leaves. As well, significant changes in free amino acids were induced by Mn concentrations higher than 300mgL-1, especially in roots. No significant changes in phenolic compounds were observed in the leaves, but root phenolics were significantly increased by increasing Mn concentrations in treatments. When Fe supply was increased 10 and 20 times (7-14mgFeL-1 as Fe-EDDHA) in the nutrient solutions at the highest Mn concentration (700mgMnL-1), it led to significant increases in photosynthetic pigments and biomass accumulation. Manganese was mostly accumulated in the roots, and the species was essentially a Mn excluder. However, considering the high leaf Mn concentration recorded without toxicity symptoms, E. andevalensis might be rated as a Mn-tolerant species.

Out-of-season spawning affects the nutritional status and gene expression in both Atlantic salmon female broodstock and their offspring

The Atlantic salmon aquaculture industry relies on adjustments of female broodstock spawning season to meet the demand for delivery of embryos outside the natural spawning season. Earlier results from zebrafish have shown that parental micronutrient status program offspring metabolism. Therefore, the main hypothesis of this study was to investigate if out-of-season (off-season) broodstock (spawning in June, in land-based recirculation systems) and their offspring deviate in micronutrient status when compared to broodstock and offspring from normal spawning season. Both seasons of female Atlantic salmon broodstock were fed the same diet and starved for approximately the same time interval prior to spawning. We compared nutrients related to the 1C metabolism (vitamin B12, folate, vitamin B6, methionine), free amino acids (FAAs) and lipid classes in broodstock muscle and liver tissues, and during offspring ontogeny. In general, the off-season broodstock showed higher levels of folate, vitamin B6 and selected FAAs in muscle tissue, and higher levels of folate and lipids (cholesterol and sphingomyelin) in liver tissue compared to normal-season. Furthermore, embryos from off-season had reduced amounts of all the measured lipid classes, like cholesterol and sphingomyelin, and lower levels of one type of folate and changes in FAAs and N-metabolites. We discovered significant differences between the seasons in mRNA levels of genes controlling fatty acid synthesis and 1C metabolism in both broodstock liver and offspring. Moreover, for genes controlling the methylation of DNA; both maintenance and de novo DNA methyltransferases (DNMTs) were expressed at higher levels in off-season compared to normal-season offspring. Our results show, in general that normal spawning season broodstock allocated more nutrients to eggs than off-season. Our results indicate a potential for improved maturation for off-season group to obtain a higher offspring growth potential, and this argues for a reassessment of the nutritional influence from broodstock to offspring and the consequences through nutritional programming.

Longitudinal Changes in Crude Protein and Amino Acids in Human Milk in Chinese Population: A Systematic Review.

More than 20% of the world population live in China, which has made significant achievement in human milk research. Part of the data that were published in Chinese were, however, unavailable to non-Chinese speakers. There was also no comprehensive overview of crude protein and amino acid levels in human milk in Chinese population. This systematic review aimed to compile the data on human milk crude protein and amino acid levels in Chinese population. After searching for and screening original research articles in both English and Chinese, 23 published from 1987 to 2019 were identified (18 in Chinese and 5 in English). The data were pooled into 9 defined lactation stages. Crude protein and amino acids (protein bound plus nonprotein bound) concentrations gradually decreased during the first 60 postpartum days and remained relatively static thereafter. The concentrations and dynamic change of crude protein and amino acids were similar to those in other populations. By contrast, the longitudinal changes in free amino acids (nonprotein bound) were less clear due to the limited data available. Several common weaknesses were identified in these studies. Our study represented the most comprehensive overview on crude protein and amino acid concentrations in human milk in Chinese population, and enhanced the knowledge of protein and amino acid intakes and requirements by Chinese infants.

기계층버섯 균사체로 발효한 나물콩의 유리 아미노산, β-Glucan 및 휘발성 성분 변화

나물콩의 이용도를 높이기 위해 나물콩을 증자, 발아, 볶음처리한 후 기계층버섯(Irpex lacteus) 균사체를 10%(v/w)접종하여 5일간(25°C, 상대습도 80%) 발효한 나물콩의 유리 아미노산, β-glucan 및 휘발성 성분을 측정하였다. 증자콩, 발아콩 및 볶음콩의 총 유리 아미노산 함량은 발효 0일에 각각 5.38±0.29, 5.68±0.76, 4.16±0.22 mg/g에서 발효 5일 후에 각각 19.42±2.32, 18.91±0.79, 23.57±1.58 mg/g으로 증가하여 기계층버섯 균사체로 발효에 의해 총 유리아미노산 함량이 3배 이상 증가하는 것으로 나타났다. 특히 γ-aminobutyric acid의 함량이 발효를 통해 2배 정도 증가한 것으로 나타났다. 증자콩, 발아콩 및 볶음콩의 β-glucan 함량은 각각 0.14±0.09%, 0.23±0.06%, 0.06±0.01%를 나타냈고, 기계층버섯 균사체를 접종한 발효 0일째 발효콩의 경우 각각 0.64±0.15%, 0.46±0.88%, 0.43±0.18%로 균사체에 의해 β-glucan 함량이 증가하는 것으로 나타났다. 발효 5일째 β-glucan 함량은 증자콩 3.16±0.65%, 발아콩 3.11±0.89%, 볶음콩 3.20±1.07%(dry basis)로 나타나 가공처리 방법에 따른 유의적 차이는 없었으나, 기계층버섯균사체 발효에 의해 모두 β-glucan 함량이 4배 이상 증가하는 것을 확인하였다(P0.05). 기계층버섯 균사체로 발효한 발효콩의 휘발성 성분은 발효 5일째 추출물에서 2-ethyl furan, n-hexanal, 1-hexanol, benzaldehyde 등 콩의 이취성분의 비율이 감소하였고, 1-octen-3-ol과 3-octanol등 CSUB8/SUB alcohol류가 특유의 중요한 휘발성 향기성분으로 나타났다. 기계층버섯 발효에 의해 나물콩의 유리 아미노산과 β-glucan 함량을 증가시키고 콩의 비린내 성분이 감소하는 것으로 나타나 나물콩의 이용도를 높일 수 있음을 확인하였다.

Response of nutritional and functional composition, anti-nutritional factors and antioxidant activity in germinated soybean under UV-B radiation

The effects of germination under UV-B radiation on the nutritional and functional composition, anti-nutritional factors and antioxidant activity of germinated soybean were comprehensively investigated. Results showed that total sugar decreased by 16% and the free amino acids increased from 0.29 to 4.73 g/100 g during germination, while UV-B inhibited these changes. UV-B increased Asp content, but reduced Glu content. Germination enhanced the level of saturated fatty acids and suppressed the proportion of unsaturated fatty acids, while UV-B further increased the linolenic acid and erucic acid contents. In addition, UV-B significantly elevated the contents of isoflavones (from 3325 to 8080 μg/g), phenolic acids (from 24 to 104 μg/g), vitamin C (from 21 to 194 mg/100 g), folate (from 783 to 1602 μg/100 g), and chlorophyll contents (from 0.007 to 0.237 mg/g) during germination, respectively. Meanwhile, enhanced antioxidant activity and reduced anti-nutritional factors were also observed in the presence of UV-B. Principal component analysis indicated that changes in free amino acid, vitamin C and folate were highly correlated with antioxidant activity. Therefore, UV-B radiation during germination is an efficient protocol to enhance the nutritional and functional qualities of soybeans.

Solid state fermentation process with Aspergillus kawachii enhances the cancer-suppressive potential of silkworm larva in hepatocellular carcinoma cells

BackgroundMulberry silkworm larvae (Bombyx mori) are known as the oldest resource of food and traditional medicine. Although silkworm larvae have been reported to treat various chronic diseases, the effect of fermentation by microorganisms improving the biological activities of silkworm larvae was not reported. In the present study, fermented silkworm larvae was developed via solid-state fermentation with Aspergillus kawachii and investigated its anti-cancer activity in human hepatocellular carcinoma cells.MethodsWe investigated the anti-cancer effects of unfermented (SEE) and fermented silkworm larva ethanol extract (FSEE) on HepG2 human hepatocellular carcinoma cells as well as compared changes in free amino acid, fatty acid, and mineral contents. Anti-cancer activities were evaluated by SRB staining, cell cycle analysis, Annexin V staining, Hoechst staining, DNA fragmentation analysis and western blot analysis. Fatty acid, free amino acid and mineral contents of SEE and FSEE were determined by gas chromatography, amino acid analyzer and flame atomic absorption spectrophotometer, respectively.ResultsCompared with SEE, treatment with FSEE resulted in apoptotic cell death in HepG2 cells characterized by G0/G1 phase cell cycle arrest, DNA fragmentation, and formation of apoptotic bodies. Furthermore, FSEE significantly up-regulated pro-apoptotic as well as down-regulated anti-apoptotic proteins in HepG2 cells. However, an equivalent concentration of SEE did not induce cell cycle arrest or apoptosis in HepG2 cells. Moreover, fermentation process by Aspergillus kawachii resulted in enhancement of fatty acid contents in silkworm larvae, whereas amino acid and mineral contents were decreased.ConclusionCollectively, this study demonstrates that silkworm larvae solid state-fermented by Aspergillus kawachii strongly potentiates caspase-dependent and -independent apoptosis pathways in human hepatocellular carcinoma cells by regulating secondary metabolites.

Relation of quality and sensory perception with changes in free amino acids of thawed seabream (Sparus aurata)

This study aimed to investigate how the freshness before frozen storage affect the quality and sensory characteristics of seabream in different commercial presentations and to correlate the findings with free amino acids composition. The fish were slaughtered, allocated to three processing treatments (whole, gutted and filleted) and stored at refrigeration (0 ±1 °C) for different times (5, 9, 11 and 18 days) before one-month frozen storage (−30 °C). After this time, physicochemical (pH, TVB-N, TBARS and free amino acids), bacterial count and sensory evaluation (Torry Index & Quality Descriptive Analysis -QDA-) were studied. Significant differences were found among treatments over time for TVB-N, TBARS and bacterial growth. The quality index (Torry) exhibited a gradual decrease. QDA showed that fillets had the lowest assessment. Free amino acids contents varied significantly during frozen storage with a particular behavior that depended on the previous treatment applied and the fish freshness degree (elapsed days before frozen).

Analysis of amino acid profiles of blood over time and biomarkers associated with non-alcoholic steatohepatitis in STAM mice.

The changes in free amino acid (AA) levels in blood during the progression from non-alcoholic steatohepatitis (NASH) to hepatocellular carcinoma (HCC) are unclear. We investigated serum AA levels, along with biochemical and histological events, in a mouse model of NASH. We induced NASH in male C57BL/6J mice with a streptozotocin injection and high-fat diet after 4 weeks of age (STAM group). We chronologically (6, 8, 10, 12, and 16 weeks, n=4–12 mice/group) evaluated the progression from steatohepatitis to HCC by biochemical and histological analyses. The serum AA levels were determined using an AA analyzer. Serum aspartate aminotransferase and alanine aminotransferase levels were higher in the STAM group than in the normal group (non-NASH-induced mice). Histological analysis revealed that STAM mice had fatty liver, NASH, and fibrosis at 6, 8, and 10 weeks, respectively. Moreover, the mice exhibited fibrosis and HCC at 16 weeks. The serum branched-chain AA levels were higher in the STAM group than in the normal group, especially at 8 and 10 weeks. The Fischer ratio decreased at 16 weeks in the STAM group, with increasing aromatic AA levels. These results suggested that this model sequentially depicts the development of fatty liver, NASH, cirrhosis, HCC, and AA metabolism disorders within a short experimental period. Additionally, serum amyloid A was suggested to be a useful inflammation biomarker associated with NASH. We believe that the STAM model will be useful for studying AA metabolism and/or pharmacological effects in NASH.

Impact of Elevated CO2 on Seed Quality of Soybean at the Fresh Edible and Mature Stages.

Although the effect of elevated CO2 (eCO2) on soybean yield has been well documented, few studies have addressed seed quality, particularly at the fresh edible (R6) and mature stages (R8). Under the current global scenario of increasing CO2 levels, this potentially threatens the nutritional content and quality of food crops. Using four soybean cultivars, we assessed the effects of eCO2 on the concentrations of crude protein, crude oil, and isoflavones and analyzed the changes in free amino acids, fatty acids, and mineral elements in seeds. At R6, eCO2 had no influence on soybean seed protein and oil concentrations. At R8, eCO2 significantly decreased seed protein concentration but increased seed oil concentration; it also significantly decreased total free amino acid concentration. However, at the same stage, the proportion of oleic acid (18:1) among fatty acids increased in response to eCO2 in the cultivars of Zhongke-maodou 2 (ZK-2) and Zhongke-maodou 3 (ZK-3), and a similar trend was found for linoleic acid (18:2) in Zhongke-maodou 1 (ZK-1) and Hei-maodou (HD). Total isoflavone concentrations increased significantly at both the R6 and R8 stages in response to eCO2. Compared with ambient CO2, the concentrations of K, Ca, Mg, P, and S increased significantly under eCO2 at R6, while the Fe concentration decreased significantly. The response of Zn and Mn concentrations to eCO2 varied among cultivars. At R8 and under eCO2, Mg, S, and Ca concentrations increased significantly, while Zn and Fe concentrations decreased significantly. These findings suggest that eCO2 is likely to benefit from the accumulation of seed fat and isoflavone but not from that of protein. In this study, the response of seed mineral nutrients to eCO2 varied between cultivars.

Changes in free amino acids and hardness in round of Okinawan delivered cow beef during dry- and wet-aging processes

BackgroundAging trials are conducted to determine characteristics associated with dry- and wet-aging processes of beef from delivered cows grown in Okinawa, i.e., dams that have finished giving birth (Okinawan delivered cow beef). Changes in free amino acids, hardness, and other factors were analyzed in round of Okinawan delivered cow beef during dry- and wet-aging processes along with a comparison with characteristics of beef imported from Australia.ResultsFunctional amino acids did not increase during both dry- and wet-aging processes. However, proteinogenic amino acids increased significantly (P < 0.05) and hardness tended to decrease during both dry- and wet-aging processes. On comparison between dry- and wet-aging processes by analysis of variance, drip and cooking losses were significantly lower during the dry-aging process than during the wet-aging process. However, there was no significant difference in free amino acids or hardness in this comparison.ConclusionThere was no significant difference between dry- and wet-aging methods for all studied variables related to free amino acids or hardness in this study.

Change of Peptides and Free -Amino Acids Contents during Nanjing Dry-Cured Duck Processing

In order to explore the relationship between the change of peptides and free-amino acid (FAA) and its unique flavour, Dry-cured duck samples of different processing phases were used to study the change of free-amino acid by High Performance Liquid Chromatography (HPLC) in this paper, meanwhile the trichloroacetic acid precipitation method for modeling use to establish the quantitative predicated peptides. The changes of small peptides and free amino acids in the process were studied. The results showed that the level and amount of proteolysis increased with the processing time at traditional technology, meanwhile the amount of peptides were positively correlated with FAA contents (R2=0.86).

Changes in free amino acid content during naupliar development of the Calanoid copepod Acartia tonsa

Changes in free amino acids (FAA) were investigated in the potentially important live feed and neritic copepod species Acartia tonsa during naupliar development. Total content of FAA in A. tonsa nauplii was around 17% of dry weight at first development stage, and declined to 6% for later stages. Relative to body-volume and biomass, the FAA content indicated possible volume-dependent changes. However, changes in FAA with osmolytic activity could not account for this decline in FAA content, but suggests that the decline reflected degradation of residual FAAs from the embryonic stage. Glutamic acid revealed the largest change in relative abundance during naupliar development and declined from 29.0% at first nauplius stage to 7.1% at later stages. The high FAA pool in early naupliar stages may be necessary for naupliar development due to an absence of feeding at first development stages. The high FAA content in early nauplii indicates that A. tonsa is a valuable source for nutritional energy for first-feeding fish larvae and should be further exploited for aquaculture purposes. Enhancements to FAA abundances in nauplii through manipulation of maternal diets could be of future interest, as copepod nauplii can contain a substantial pool of FAAs at first development stage.

Effect of high pressure processing and storage on the free amino acids in seedlings of Brussels sprouts

Abstract The potential of high pressure (HP) to affect the content of free amino acids (FAA) using seedlings of Brussels sprouts as a simple non-chopped vegetable system was examined. Firstly, the effect on FAA composition during growth was assessed and it was found that the composition of total free amino acids (TFAA) and individual FAA changed dramatically during growth of the seeds to the seedling at 7 days with the highest content of TFAA. Secondly, 7-day-old seedlings were HP-treated at various pressure levels (200–800 MPa for 3 min at 5 °C). As expected the HP-treatment did not affect the amino acids as no changes in TFFA were found immediately after pressurisation. In this line, HP-treatment up to 800 MPa had minor, but significant, effect on the FAA concentrations of 10 FAA (Ala, Asp, Glu, Gly, Leu, Phe, Pro, Ser, Trp and Tyr) and no significant changes were found for 7 of the FAA (Asn, Gln, His, Ile, Lys, Thr, and Val) concluding that the short pressure time (3 min) was insufficient to activate indigenous proteolytic enzymes. Furthermore, changes in the FAA content and composition of HP-treated seedlings during storage (0, 1, 2, and 4 days at 4 ± 2 °C) were evaluated in order to assess changes in the proteolytic enzyme activity. It was found that the changes in FAA differed according to the specific amino acids as well as the HP processing conditions and the subsequent storage time. These results suggest that HP treatment affects proteolysis and/or certain amino acids metabolism pathways in Brussels sprouts seedlings after HP treatment and during subsequent storage.

Effects of long-term frozen storage on the compositions of free amino acids and nucleotide-related compounds of the coconut crab Birgus latro

This study examined the effects of long-term frozen storage (-20 °C for 5 months) of free amino acids (FAAs) and nucleotide-related compounds (NRCs) in muscle and hepatopancreas of the coconut crab Birgus latro. Although long-term frozen storage had little effect on FAA composition in muscle, the amounts of several FAAs increased in the hepatopancreas that may be the result of protein decomposition during the frozen storage. Long-term storage at -20°C significantly increased the amounts of disodium 5ʹ-inosine monophosphate (IMP) in muscle and hepatopancreas, resulting from the deaminase activity of 5ʹ-adenosine monophosphate (AMP) which deaminates AMP to IMP. Changes in FAAs and NRCs may result in changes in the flavor of muscle and hepatopancreas of frozen stored coconut crabs, both through altered amounts of each substance and synergistic interactions among substances.

Amino acid composition of royal jelly harvested at different times after larval transfer.

The amino acids in royal jelly (RJ) have a wide range of pharmacological and health-promoting functions in humans. Multiple studies on the amino acid quality and composition in RJ have investigated RJ harvested at 72 h after larval transfer. In contrast, the concentration of amino acids in RJ harvested before 72 h remains unknown. In this study, the concentration of free amino acids (FAAs) and total amino acids (TAAs) in RJ harvested at 13 time points between 24 and 72 h after transfer of ten Apis mellifera colonies were measured. Our results indicated that the most abundant FAAs were Pro, Phe, Lys, Glu, and Tyr, whereas the most abundant TAAs were Asp, Glu, Leu, Lys, and Val. The total FAA concentration in RJ increased with increasing harvest time, from 4.30 mg/g at 24 h to 9.48 mg/g at 72 h. In contrast, the variation in concentration of TAAs observed was a decrease-increase-decrease trend with 40 h (149.53 mg/g) and 52 h (169.62 mg/g) as inflection points. The highest and lowest concentrations of TAA were 197.96 and 121.32 mg/g at 24 and 72 h, respectively. To our knowledge, this is the first study to investigate the concentration changes of FAAs and TAAs prior to 72 h after transfer. Our results will provide theoretical support to guide production practices of beekeeping, as well as elucidate the relationship between the harvest time point and RJ content.

Changes in free amino acid and monoamine concentrations in the chick brain associated with feeding behavior.

Domesticated chicks are precocial and therefore have relatively well-developed feeding behavior. The role of hypothalamic neuropeptides in food-intake regulation in chicks has been reported for decades. However, we hypothesized that nutrients and their metabolites in the brain may be involved in food intake in chicks because these animals exhibit a very frequent feeding pattern. Therefore, the purpose of this study was to examine the feeding behavior of chicks as well as the associated changes in free amino acid and monoamine concentrations in the chick brain. The feeding behavior of chicks was recorded continuously for 6 h. The next day, brain and blood samples were collected when the chicks either attempted to have food (hungry group) or turned food down (satiated group), in order to analyze the concentrations of the free amino acids and monoamines. We confirmed that the feeding behavior of neonatal chicks was characterized by short resting periods between very brief times spent on food intake. Several free amino acids in the mesencephalon were significantly lower in the satiated group than in the hungry group, while l-histidine and l-glutamine were significantly higher. Notably, there was no change in the free amino acid concentrations in other brain regions or plasma. As for monoamines, serotonin and norepinephrine were significantly lower in the mesencephalon of the hungry group compared with the satiated group, but 5 hydroxyindolacetic acid (5-HIAA) was higher. In addition, serotonin and norepinephrine levels were significantly higher in the brain stem of the hungry chicks compared with the satiated group, but levels of 5-HIAA and homovanillic acid were lower. Levels of both dopamine and its metabolite, 3,4-dihydroxyphenylacetic acid, were significantly higher in the diencephalon and telencephalon of the chicks in the hungry group. In conclusion, the changes in the free amino acids and monoamines in the brain may have some role in the feeding behavior of neonatal chicks.

Nitrogen effect on amino acid composition in leaf and grain of japonica rice during grain filling stage

This paper reports the effect of nitrogen on amino acid composition of leaf and grain for japonica rice during the grain filling stage, using pot experiments with three N rate treatments. Dynamic changes of free amino acids (FAA) and protein amino acids (PAA) in leaves and grains were monitored. Results showed that FAA in leaves decreased with the progress of grain filling. FAA in grains increased at first 14 days after anthesis and then decreased to a nearly constant level. PAA in leaves showed a diminishing trend as leaf senesced after anthesis. Conversely, PAA in grain exhibited an increasing trend with the progress of grain filling. N had significantly positive effect on contents of FAA and PAA in leaves and grains. There was no obvious trend of the variation of FAA in leaves and grains with N rates. PAA in leaves was more sensitive to N fertilization. By contrast, PAA in grains was more stable across N rates, especially at the late stage of grain filling. In addition, composition of leaf PAA was different from that of grain, indicating the reconstruction of amino acids during the process of translocation of N compounds from leaves to grains.